Bethesda was pretty good about keeping the lid on tight on the news that they were doing a Skyrim remaster. That is until the weeks before E3 and nobody could keep their mouths shut. Remasters are a (relatively) new business that hasn't really boomed until this console generation, so it's no surprise that such a legendary game like Skyrim would get the treatment, but it's not Bethesda's only great work, or even great Elder Scrolls game. Some fans still prefer 2006's Oblivion, and might be wondering why the studio chose to do Skyrim instead.
Well, the answer is simple. Would you rather have a remaster or an all-new game?
Pete Hines talked about the process with Gamespot and revealed that Bethesda had considered Oblivion for a remaster, but said that the amount of work to do so was equivalent to making a brand new game. He said:
"Oblivion is 10 years old, so the amount of work for that engine and that tech to bring it and remaster it and do all the things we wanted to do was significant…It's not impossible, but it was mountainous. It was either like, go make an entire new game or do Skyrim."
By doing a Skyrim remaster, it makes it much more feasible for the studio to get to work on a brand new Elder Scrolls game sooner, using the money made from a Skyrim remaster to help advance the project. So it made sense from both a business and creative standpoint to choose Skyrim over Oblivion at least at this time. Hines never actually says that an Oblivion remaster is completely off the table, I just wouldn't hold my breath for one. At least anytime soon.
Source: [Gamespot]
